UNIVERSITY  OF   CALIFORNIA 

COLLEGE    OF  AGRICULTURE 

BERKELEY 


AGRICULTURAL    EXPERIMENT    STATION 

BENJ.    IDE    WHEELER,    PRESIDENT 
THOMAS    FORSYTH    HUNT,   Dean  and  Director 
H.    E.    VAN    NORMAN,    Vice- Dm ector    and    Dean 
University   Farm    School 


CIRCULAR  No.  115 
February,  1914 


GRAFTING  VINIFERA  VINEYARDS 

By  FREDERIC  T.  BIOLETTI 


For  various  reasons,  growers  often  wish  to  change  the  variety  of 
grapes  which  they  are  growing.  There  are  two  ways  of  doing  this. 
One  is  to  dig  up  the  old  vines  and  plant  new.  The  other  is  to  graft 
over  the  old  vines  with  the  desired  variety. 


Fig.  1 

Tools  for  Grafting  Vines 


As  a  rule  it  is  a  mistake  to  follow  either  of  these  courses.  If  the 
price  of  one  kind  of  grape  is  low  now,  by  the  time  the  change  is  made, 
the  new  kind  may  have  fallen  in  price  and  the  old  one  be  more  profit- 
able. In  any  case,  there  is  considerable  expense  and  loss  of  time  and 
material,  which  only  very  considerable  improvement  in  crop  and  price 
will  compensate.  There  are,  however,  some  cases  where  a  change  of 
this  kind  is  advisable,  and  at  all  events  there  is  always  somebody  ready 
to  take  the  risk,  and  it  is  desirable  to  make  this  risk  as  small  as  pos- 
sible by  doing  the  work  properly. 


Grafting  may  also  be  used  to  change  undesirable  varieties  in  mixed 
blocks.  Scattering  wine  grapes  in  a  vineyard  of  shipping  or  raisin 
grapes  are  wasted  or  are  expensive  to  harvest.  These  can  be  best 
utilized  by  grafting  with  the  variety  of  which  the  block  is  mainly 
composed. 

Two  Kinds  of  Grafting. — Most  of  the  late  publications  on  grafting 
vines  refer  to  grafting  Vinifera  varieties  on  American  or  phylloxera 
resistant  stocks.  This  differs  in  several  important  respects  from  the 
grafting  of  one  vinifera  variety  on  another,  which  we  are  now  con- 
sidering, and  methods  suitable  for  one  case  would  be  defective  for 
the  other.* 

Age  of  Vines. — Vinifera  vines  may  be  grafted  at  any  age,  but  there 
is  seldom  anything  to  be  gained  by  grafting  vines  less  than  2  or  3  years 
old.  For  younger  vines,  it  is  usually  cheaper  and  better  to  dig  up  and 
replant,  if  a  change  is  necessary.  Very  old  vines  (12  years  or  over), 
if  they  are  sound  and  straight  below  the  soil,  may  be  grafted  success- 
fully. Such  grafted  vines,  however,  are  usually  short-lived.  The 
large  wounds  and  the  great  amount  of  wood  which  decays  often  make 
unhealthy  vines.  In  deep,  loose,  dry  soil  the  stumps  of  such  vines 
may  be  removed  entirely  and  the  grafts  inserted  in  the  roots.  This 
requires  great  skill,  however,  and  the  percentage  of  failures  is  always 
large.  Vines  of  from  three  to  eight  years  are  the  most  easily  and 
successfully  grafted. 

Choice  of  Scions. — Preparations  for  grafting  should  be  commenced 
early  by  choosing  good  healthy  mother  vines  bearing  good  crops  from 
which  to  take  the  cuttings  to  be  used  as  scions. 

As  late  grafting  is  usually  the  most  successful,  it  is  desirable  to 
keep  the  scions  dormant  as  long  as  possible.  For  this  purpose  the 
cuttings  should  be  taken  from  the  vines  when  their  activities  for  the 
season  have  completely  ceased  and  those  of  the  next  season  have  not 
commenced.  Wait,  therefore,  until  all  the  leaves  have  fallen  off  the 
mother  vines  for  one  or  two  weeks.  Any  time-  from  this  until  a  month 
before  the  swelling  of  the  buds  is  suitable. 

Cuttings  taken  within  a  week  or  two  after  the  fall  of  the  leaves  are 
the  best.  The  cuttings  should  be  carefully  selected  and  only  good 
sound  canes  of  medium  size,  with  eyes  neither  too  close  nor  too  far 
apart  should  be  used. 

Conservation  of  Scions. — It  is  convenient  to  make  the  cuttings  long 
enough  for  2  scions,  allowing  2  extra  eyes  for  waste.  This  length  will 
be  from  14  to  24  inches,  according  to  variety  and  the  length  of  scion 
used.    The  cuttings  should  be  made  up  into  small  bundles  of  50  to  100 


*  For  grafting  resistant  vinos  sec  Bull.  180,  " Resistant  Vineyards.' 


and  stored  in  a  cool  and  moderately  dry  place.  The  best  way  is  to  put 
them  into  pits  or  trenches  under  an  open  shed,  and  cover  them  com- 
pletely with  very  slightly  moist  sand.  Any  shady  place  where  there 
is  no  danger  of  too  much  moisture  getting  to  the  cuttings  may  be  used, 
such  as  under  a  dense  tree,  the  north  side  of  a  building,  a  cellar,  etc. 

Season  for  Grafting. — The  best  time  for  grafting  depends  some- 
what on  the  soil  and  the  climate,  but  usually  the  latest  grafts  do  the 
best,  providing  the  scions  are  completely  dormant  and  otherwise  in 
good  condition.  If  the  buds  of  the  scions  have  started  and  the  bark 
become  loose,  many  will  fail. 

In  well  drained,  sandy  soil,  the  time  for  successful  grafting  extends 
from  January  to  May  in  most  localities,  but  March  for  the  earlier  and 
April  for  the  later  localities  are  usually  the  best  months.  In  stiffei 
and  wetter  soils,  much  greater  care  is  necessary  in  choosing  the  time 
for  grafting.  The  soil  should  be  in  such  condition  that  it  will  pulverize 
easily,  and  the  heavy  rains  should  be  over.  Lumpy  soil  placed  about 
the  graft  will  cause  many  failures,  and  a  heavy  rain  which  leaves  the 
soil  water-logged  around  the  union  for  several  days  may  kill  all 
of  them. 

It  is  best  in  all  cases  when  possible  to  wait  until  the  buds  com- 
mence to  swell  on  the  vines  to  be  grafted,  and  grafting  may  continue 
until  the  shoots  are  several  inches  long  or  longer. 

Preparation  of  the  Stock — More  grafts  fail  from  an  excess  of 
moisture  than  from  drying  out.  This  moisture  may  be  already  in  the 
soil,  or  due  to  rains  after  grafting,  or  it  may  simply  be  due  to  the  sap 
which  flows  out  of  the  cut  stump.  The  amount  of  sap  that  will  flow 
out  of  a  vine  2  or  more  inches  in  diameter  is  very  considerable  and 
quite  sufficient  in  many  cases  to  "drown"  the  graft.  This  may  be 
avoided  by  cutting  off  the  vines  1  or  2  days  before  grafting  and  leav- 
ing them  exposed  to  the  air,  in  order  that  the  main  flow  of  sap  may 
dry  up.  This  is  good  practice  in  all  cases  where  the  vines  are  over  iy2 
inches  in  diameter. 

Met! tods  of  Grafting. — Many  methods  have  been  recommended 
and  used  for  old  vines,  but  the  ordinary  cleft  graft  is  the  easiest,  and 
if  done  under  proper  conditions  will  give  a  practically  perfect  stand. 

Tools  Necessary. — The  only  special  tools  needed  are  a  curved 
pruning  saw,  a  grafting  or  budding  knife,  a  wooden  maul,  and  a 
strong  i/>-inch  chisel,  unless  the  vines  are  very  large,  that  is,  over  3 
inches  in  diameter.  In  this  case,  it  is  well  to  have  a  grafting  tool 
made.  Any  blacksmith  can  make  a  good  one  from  an  old  horseshoe 
file.  This  tool  should  be  14  inches  long  and  about  %  of  an  inch  in 
diameter.    At  one  end  it  should  be  flattened  out  into  a  hatchet  shaped 


blade  3  inches  long  and  2  inches  wide.  This  blade  should  be  about  % 
of  an  inch  thick  on  the  back,  gradually  tapering  to  a  sharp  edge.  The 
other  end  of  the  tool  should  be  shaped  like  a  cold  chisel  about  %  of 
an  inch  wide.  This  cold  chisel  edge  should  be  in  the  same  plane  as 
the  hatchet  edge  and  not  at  right  angles  to  it  as  is  sometimes  made. 
(See  fig.  1 


A  convenient  receptacle  for  holding  the  scions  is  made  by  cutting 
a  coal  oil  can  horizontally  through  the  middle  and  placing  a  round 
stick  across  the  top  for  a  handle.  This  will  hold  50  or  more  scions, 
and  by  putting  an  inch  of  water  in  the  bottom,  they  can  be  kept 
perfectly  fresh. 


Preparation  of  the  Scions. — Proper  care  of  the  scions  is  necessary 
for  the  best  results.  If  the  cuttings  have  been  made  and  kept  properly, 
they  will  show,  on  being  cut,  clear  greenish  white  wood,  green  inner 
bark,  and  firm,  dry,  light-brown  pith.  If  the  pith  is  black  or  water- 
soaked,  the  wood  streaked  or  spotted  with  black,  or  the  bark  loose  or 
brownish,  the  cuttings  have  been  injured  by  too  much  moisture  or  they 
were  poor  cuttings  to  commence  with,  and  should  not  be  used. 

A  cutting  which  is  too  dry  is  harder  to  detect  by  its  appearance. 
If  suspected  of  being  too  dry,  they  may  be  tested  by  placing  2  or  3 
short  pieces  of  2  or  3  buds  in  moist  sand  in  a  warm  room.  If  in  a 
week,  they  do  not  show  signs  of  life  by  the  starting  of  the  roots  at 
the  bottom  or  the  swelling  of  the  buds,  they  are  unsafe  to  use. 

Twenty-four  hours  before  they  are  needed,  the  cuttings  should  be 
taken  out  of  the  sand  in  which  they  have  been  stored  and  washed  to 
remove  all  particles  of  sand  which  would  blunt  the  grafting  knife. 
They  should  then  stand  in  fresh  water  for  1  or  2  days,  but  not  more, 
until  used. 

Method  of  Operating. — The  first  thing  to  do  is  to  clear  away  the 
earth  from  around  the  base  of  the  vine,  making  a  pit  about  2  feet  in 
diameter  and  2  to  3  inches  deeper  than  the  level  at  which  the  grafting- 
is  to  be  done.  The  earth  should  be  well  cleaned  off  the  stem  of  the 
vine  and  the  rough  dry  bark  removed  (see  A,  fig.  2).  The  vine  is  then 
ready  for  decapitation.  This  is  done  by  sawing  horizontally  in  such 
a  place  that  about  2  inches  of  smooth,  straight  grain  are  left  at  the 
top  (See  S,  fig.  2).  If  the  sawing  is  done  at  or  too  near  a  place  where 
the  grain  of  the  wood  is  crooked  or  curly,  great  difficulty  will  be  found 
by  the  grafter  in  making  a  good  fit. 

After  leaving  the  decapitated  vine  about  24  hours  to  bleed,  it  is 
ready  for  the  insertion  of  the  scion.  If  the  vines  are  iy2  inches  in 
diameter  or  less,  one  scion  to  each  vine  is  sufficient.  An  attempt  to 
put  in  more  will  usually  result  in  having  2  badly  fitting  grafts  in 
place  of  1  good  graft.  For  larger  vines,  2  scions  are  preferable  when- 
ever they  can  both  be  made  to  fit  securely.  If  both  of  these  scions 
grow,  the  weaker  is  removed  at  the  next  pruning.  In  making  the  cleft, 
a  place  should  be  chosen  where  the  bark  is  smooth,  straight  and  sound. 
The  cleft  should  be  made  by  splitting,  not  by  cutting.  First  place 
the  edge  of  the  knife  or  grafting  tool  on  the  part  of  the  sawed  surface 
where  the  cleft  is  to  be  made,  and  which  has  been  previously  cleaned 
and  smoothed  with  the  grafting  knife.  With  a  slight  blow  of  the 
wooden  mallet  the  edge  is  driven  about  Vs  °f  an  mcn  into  both  wood 
and  bark  (See  C,  fig.  2).  The  object  of  the  mark  thus  made  is  to 
insure  that  the  bark  and  the  wood  split  at  the  same  place.    The  chisel 


or  the  chisel  end  of  the  grafting  tool  is  then  placed  on  the  mark 
sufficiently  far  from  the  bark  to  allow  of  the  insertion  of  the  scion 
and  then  driven  in  an  inch  or  so,  sufficient  to  open  a  cleft  wide 
enough  to  allow  the  entrance  of  the  scion  (See  D,  fig.  2).  The  open- 
ing of  the  cleft  is  accomplished  by  pressing  the  chisel  sideways.  The 
scion  is  inserted  and  then,  when  the  chisel  is  released  and  removed, 
the  tension  of  the  wood  will  hold  the  scion  firmly  in  place  (See  E, 
fig.  2). 

The  cleft,  whenever  possible,  should  not  extend  quite  across  the 
vine.  If  the  cleft  extends  only  part  way,  it  will  close  up  more  com- 
pletely and  hold  the  scion  more  firmly.  With  small  vines,  it  is  often 
impossible  to  avoid  splitting  quite  across,  and  it  may  then  be  neces- 
sary to  tie  the  scion  in  by  putting  2  or  3  turns  of  thin  string  or  raffia 
around  the  stock.  With  large  vines,  the  pressure  is  occasionally  too 
great,  and  sufficient  to  crush  the  scion.  This  is  obviated  by  placing  a 
small  wedge  of  wood  immediately  behind  the  scion. 

Sit  aping  the  Scions. — The  scion  is  cut  in  the  ordinary  wedge  form, 
a  little  thicker  on  the  side  which  comes  nearest  to  the  bark.  The 
length  of  the  wedge  depends  on  the  character  and  size  of  the  cleft  in 
the  stock.  The  wedge  will  usually  be  long  and  tapering.  It  is  in- 
serted in  such  a  way  that  the  line  between  the  bark  and  wood  coincide 
with  the  corresponding  line  on  the  stock.  As  the  bark  of  the  stock 
is  thicker  than  that  of  the  scion  the  outer  surface  of  the  scion  will  be 
a  little  lower  than  that  of  the  stock.  It  is  not  always  possible  to  make 
the  lines  correspond  exactly,  but  perfectly  satisfactory  unions  are 
obtained  if  these  lines  were  very  near  together  or  cross  in  one  or 
two  places. 

The  cutting  of  the  scion  should  be  done  with  a  very  sharp,  clean 
knife,  and  its  insertion  in  the  stock  should  be  immediate,  before  it 
has  a  chance  to  become  dry  even  on  the  surface.  It  is  bad  practice  to 
prepare  the  scions  beforehand. 

After  the  Scion  is  Set. — As  soon  as  the  scion  is  in  place,  all  cut 
surface  of  stock  and  scion  should  be  carefully  covered  with  a  couple 
of  inches  of  moist,  well-pulverized  soil  (see  H,  fig.  2),  and  a  stake 
driven  in  such  a  position  that  it  will  support  the  first  growth  of  the 
graft.  The  complete  filling  of  the  hole  may  be  deferred  for  a  few 
hours,  except  in  extremely  hot,  dry  weather,  but  not  long  enough  to 
run  any  risk  of  having  the  scion  become  even  slightly  dry.  No  wax, 
clay  or  similar  material  is  needed.  There  is  nothing  better  to  put 
around  the  union  than  moist,  loose  soil.  This  gives  the  conditions  of 
moisture  and  aeration  most  favorable  to  the  uniting  of  the  tissues.  It 
is  a  good  practice  to  cover  the  cleft  in  the  stock  with  a  little  clay,  a 


leaf,  or  anything  that  will  exclude  the  soil,  but  unless  the  cleft  is  large, 
this  is  not  necessary.  The  filling  up  of  the  hole  with  soil  should  be 
complete  and  the  whole  scion  may  be  covered  up  unless  the  soil  has  a 
tendency  to  bake.  When  finished,  each  graft  will  be  in  the  middle  of 
a  wide  mound  of  soil  (See  H2,  fig.  2).  Narrow  mounds  may  become 
too  dry. 

Length  of  Scion. — It  is  usual  to  use  scions  of  two  buds,  but  there 
is  often  advantage  in  having  them  longer.  Three  and  even  more,  buds 
have  been  used  with  advantage  on  large  vines.  With  only  2  buds  on 
such  vines  the  growth  is  often  so  rapid  and  so  large  as  to  be  almost 
unmanageable.  With  several  buds,  it  is  sometimes  possible  to  obtain 
5  or  6  bunches  of  grapes  the  first  year,  which,  if  the  variety  is  early, 
will  ripen  sufficiently  for  wine-making. 

After  Treatment  of  the  Grafts. — The  proper  management  of  the 
grafts  during  the  first  growing  season  is  as  important  as  the  grafting 
itself. 

The  mounds  should  not  be  disturbed  by  hoe  or  cultivator  until  the 
unions  are  well  formed.  If  the  scions  are  completely  covered  and  the 
mounds  form  a  hard  crust,  this  crust  should  be  carefully  broken  with 
the  fingers. 

Suckering. — Many  large,  vigorous  shoots  will  come  up  from  the 
old  stock.  If  these  are  left  too  long,  they  will  choke  or  dwarf  the 
graft.  If  they  are  removed  too  soon,  many  good  grafts  will  be  dis- 
turbed and  killed  by  injuring  the  unions.  Judgment  and  careful  work 
are  therefore  needed  in  suckering.  When  the  grafts  have  started  to 
grow  vigorously,  so  that  the  shoots  can  be  tied  to  the  stake,  it  is  safe 
to  commence  suckering.  The  suckers  can  usually,  at  this  time,  be 
removed  in  bunches  by  pulling  up  by  the  hand  without  removing  any 
soil.  Unless  it  is  quite  certain  that  the  suckers  are  not  entangled  with 
the  scion,  some  soil  must  be  carefully  removed  until  it  is  possible  to 
see  how  to  detach  the  suckers  without  disturbing  the  union. 

Where  grafts  are  slow  in  starting,  and  the  suckers  vigorous,  it  is 
necessary  to  sucker  before  the  scion  has  grown  much.  This  can  be  done 
safely  if  care  is  used. 

Tying  Up  the  Shoots. — When  the  union  is  complete,  the  growth  of 
the  grafts  on  large  vines  is  generally  very  rapid.  A  growth  of  2  or  3 
inches  a  day,  and  many  canes  10  to  15  feet  long  on  a  vine  at  the  end 
of  the  season,  is  common.  Unless  this  vigorous  growth  is  properly 
managed  its  benefits  are  not  only  lost,  but  it  gives  great  trouble  the 
following  year  and  makes  it  impossible  to  obtain  a  properly  shaped, 
healthy  vine.  If  the  canes  are  left  to  themselves  they  will  often  grow 
flat  on  the  ground,  and  as  they  may  be  iy2  inches  thick  or  more  by  the 


8 

end  of  the  season,  the  attempt  to  raise  them  up  the  next  year  will 
result  in  many  of  the  finest  grafts  being  torn  out  of  the  stock,  and 
the  rest  will  make  ill-shaped  vines,  weakened  by  numerous  large 
wounds. 

The  shoots  should  therefore  be  tied  to  the  stake  with  a  loose  piece 
of  string  or  thin  rope  as  soon  as  they  are  long  enough.  If  too  many 
shoots  start,  they  should  be  thinned.  This  thinning  should  be  done 
early,  in  order  to  throw  all  the  available  strength  and  growth  into 
the  shoots  left.  One  shoot  to  each  bud  is  enough  on  strong  vines,  and 
one  shoot  to  a  graft  on  weak  or  small  vines. 

When  the  shoots  left  have  grown  2  or  3  feet,  they  should  be  cut 
back  6  inches  or  so,  in  order  to  force  out  laterals.  The  laterals  which 
start  below  8  or  10  inches  from  the  base  of  the  shoot  should  be  pinched 
off  when  small,  but  all  laterals  above  that  allowed  to  grow.  The  new 
vine  is  thus  completely  formed  the  first  season,  the  main  shoot  forming 
the  trunk  of  the  vine  and  the  laterals  the  2,  3  or  4  branches.  Such  a 
vine  may  produce  almost  a  full  crop  the  following  year. 

The  cost  of  grafting  over  an  old  vineyard  properly  will  in  all  cases 
be  considerable,  and  will  seldom  be  less  than  $25  per  1000  vines  above 
the  ordinary  cost  of  cultivation,  and  without  reckoning  the  cost  of 
stakes  and  the  loss  of  crop.  With  large  vines,  the  cost  may  con- 
siderably exceed  this. 


